


A Promise of Forever

by ch_errywrites



Series: 25 Days of Malec: Christmas Edition [14]
Category: Shadowhunters (TV)
Genre: 25 Day Holiday OTP Challenge, 25 Days of Christmas Prompt Challenge, 25 Days of Fic, 25 Days of Fic-mas, Alec Lightwood Deserves Nice Things, Alec Lightwood Loves Magnus Bane, Bottom Magnus Bane, Cuddling & Snuggling, Cute, Cute Alec Lightwood, Cute Magnus Bane, Cute Magnus Bane/Alec Lightwood, Domestic Magnus Bane/Alec Lightwood, Explicit Sexual Content, Fluff, Fluff and Smut, Happy Magnus Bane/Alec Lightwood, Idiots in Love, Immortal Alec Lightwood, Immortality, M/M, Magnus Bane Deserves Nice Things, Magnus Bane/Alec Lightwood Fluff, Married Magnus Bane/Alec Lightwood, Post-Canon, Promises, Sexual Content, Tooth-Rotting Fluff, Top Alec Lightwood
Language: English
Status: Completed
Published: 2019-12-15
Updated: 2019-12-15
Packaged: 2021-02-26 07:28:15
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,031
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21789805
Author URL: https://archiveofourown.org/users/ch_errywrites/pseuds/ch_errywrites
Summary: 25 days of Malec: Christmas EditionDay 14: Promise
Relationships: Magnus Bane/Alec Lightwood
Series: 25 Days of Malec: Christmas Edition [14]
Series URL: https://archiveofourown.org/series/1560001
Comments: 1
Kudos: 67
Collections: Favorite Malec Stories





	A Promise of Forever

**Author's Note:**

> Oops, I'm posting this super late because it took much longer than planned to write it.
> 
> Just so you can't say I didn't warn you,,, for those of you who don't read the tags this one has smut in it and that would be why its 2000 words :) so you can't say I didn't warn you
> 
> I hope you all enjoy!

It may have been only a few days since Alec and Magnus went shopping together, but the thing that Alec had bought his husband was burning a hole in his pocket. It had been so hard to not just give it to Magnus. His husband was always so endearing and gorgeous it was hard for Alec to hold back, but he had managed. Though, seeing Magnus last night, watching him take care of people and keep Ragnors spirit alive, Alec knew that he couldn't hold back any longer.

They had nothing planned for the day, no work, no family matters, nothing. It was rare for both of them and Alec was going to use it to his advantage.

They were curled up under a few blankets on the couch together. Their morning had been amazing, Alec had cooked breakfast for the two of them, they giggled over some random Christmas movie that was playing as they ate their food and drank their coffees.

Magnus was tucked into his side, under his arm, his legs thrown over Alec's thighs. His husband was quiet, relaxed and content and it always made pride well up in Alec's chest knowing that he made Magnus so happy even when they were doing something as simple as sitting on the couch together.

Alec, as carefully as possible so ensure that Magnus didn't feel him move too much, reached down into his sweatshirts pocket and pulled out the little velvet box that he bought along with Magnus' present. There was another part to it, one that Alec had spent many hours on occasion with Catarina looking for. Alec took a deep breath, hoping with his whole being Magnus would agree.

"Sweetheart?"

Magnus hummed, tilting his head back a little so he could look at Alec. "Yes?"

"Do you," Alec cleared his throat, looking at Magnus and examining every detail of his face. "Do you remember the day we saved you from Edom?" He asked.

Magnus made a little noise on the back of his throat, like it was impossible for him to ever forget.

"Of course I do. Alexander, that was one of the best days of my life. How could I ever forget?

Alec smiled, ignoring the question Magnus asked. He'd never forget it either. "Do you remember what I said to you after he hugged? How I promised to never leave you again." His hand was staring to get a little clammy, but he ignored it.

Magnus looked confused and a little surprised, "Yes? But what does that have to do with any-"

Alec cut him off by pressing his finger to Magnus' lips. "Just, let me talk okay?" When Magnus pressed a kiss to his finger and nodded did Alec love his hand, reaching to grab Magnus' hand instead. "When I said those words to you, I meant them. I never want to leave you ever again. Which is why I started talking to Cat."

Alec saw Magnus' eyes widen, he had definitely figured out where this conversation was going right away and his mouth opened but Alec spoke before he could.

"Shh. I know what you're going to say Magnus." Alec took a deep breath, smiling at his husband. "I know you're going to try to convince me that immortality is the worst thing in the world and that it causes more hurt than happiness. Maybe that's been true for you up until now, but how horrible can it be with you by my side?"

Magnus didn't answer, but Alec could see in his eyes that there was so much more than that.

Alec squeezed his hand and continued, "I understand that it can be hard. I understand that making this choice means that I'll have to watch my family grow old and I'll lose them. It's going to be hard, I've already accepted that. But, I'll also have you the whole time to help me out of those dark places. I'll be able to see Izzy, Jace and Max's kids grow up, then their kids and so on. I'll watch generations of this family grow up and that itself is more than I could ask for."

Even as he was saying all of that, he knew what Magnus was thinking and he was hoping he could convince his husband differently.

"Magnus, I want to spend the rest of my life with you, but I want to also spend the rest of  _ your  _ life with you. I'll never resent you for this, this is my choice. All I want to do is love you for as long as you deserve." Alec whispered the last sentence, pressing their foreheads together.

Magnus sniffles softly, "Alexander, I don't-"

Alec shook his head and cut him off, "You don't have to say anything yet, we have plenty of time to make this decision."

He pulled his hand out of his pocket, watching Magnus' eyes widen when he saw the box and he shifted to face him directly. He found it a little funny that Magnus' reaction was being so surprised, as if they weren't already married.

Alec opened the box, showing Magnus the ring that he'd found the other day. It was silver, just like their wedding rings but it had a yellow stone in the middle, similar to his husbands mark.

"This is a promise," Alec said, showing Magnhs the ring. "A promise that no matter what you say I will always love you. That I promise I won't be mad if you don't want this. That even if you say no, I promise to still love you until we part. So even if you say no, will you accept this promise?"

By the time Alec was done, Magnus had started crying quietly. "Of course I want to spend the rest of our lives with you, Alexander. There's nothing I want more." He nodded as he spoke, "I accept."

Alec laughed softly, a tiny part of himself had actually feared Magnus would say no. He pressed a passionate kiss to Magnus' lips, sliding the ring onto his finger right in front of his wedding ring. When he pulled away he had to wipe a few tears off of his husbands cheeks.

"You are the best thing that's ever happened to me."

Magnus sniffles, leaning into his hand. "I love you, Alexander."

"I love you too, sweetheart."

Alec gently pulled Magnus closer by the hips, kissing him again. He tilted his head to deepen it, wrapping his arms around Magnus so he could lift his husband up and onto his lap. Magnus moved naturally with him, straddling Alec's thighs and pressing their bodies together.

Alec smiled against his husbands lips, cupping Magnus' cheek. They pulled away from each other and Alec almost instantly started peppering kisses down Magnus' new. He started sucking and nibbling marks all the way down his neck and over his collarbone. The sounds that Magnus made with each mark had all of his blood run south.

"Take me to bed Alexander?"

Magnus' breath brushed again his ear as he spoke, the feeling along with the words tore a groan from his throat. He reached over for his stele, Magnus moved back to watch as he activated his strength and stamina runes. Magnus took the chance to pull off his shirt, making him shiver as the warlock ran his tab his hands down his abs, little sparks bouncing off his stomach.

He used Magnus being distracted to take the chance to lift them both up, smiling when it was Magnus' first instinct to cling to him, his legs tightening around his waist.

Alec carried Magnus into their bedroom, kicking the door closed behind them. Magnus giggled when he was tossed onto the bed, making a come hither movement at him and who was Alec to deny him anything he asked for. Alec climbed on the bed in between his spread thighs, humming when their hips pressed together.

Alec undressed Magnus first, taking his time to savor every inch of skin that was revealed, leaving his husband covered in blossoming red bruises. He listened to every moan that left the warlocks lips. Magnus started to get desperate, snapping his fingers to get rid of the rest of his clothes. Alec laughed softly just like he did every time it happened.

"Get on all fours baby," Alec mumbled, reaching over the bed to get the lube.

Magnus eagerly did as told, moaning softly when Alec grabbed two handfuls of his ass. Alec licked his lips before he leaned forward, gently pushing in between Magnus' shoulder blades until his chest was pressed into the bed. His husband followed along smoothly and Alec couldn't help but praise him.

"You're so beautiful, sweetheart. Always listen so well."

Magnus moaned against the words, a soft moan leaving his lips when Alec ran his hands up his back.

Alec pressed kisses to his hips, nipping her and there as he opened Magnus up, taking his time to press his fingers as deep as he could and rub at his prostate until Magnus was on edge and practically begging him to let him come. Alec was left breathless each time, Magnus' body moving perfectly in sync with his own, hip grinding back. When he felt he was loose enough, Alec removed his fingers and eagerly lube himself up.

He took a few extra seconds to examine his husband, looking at the swell of his ass, the arch of his back and the way his face was pressed in the pillow. God, he was so fuckimg lucky. Alec was positive no angel was as beautiful as his.

He was left breathless once again when he pressed into Magnus' hest, the grip tight making him groan along with Magnus as they both got the relief they were looking for. Magnus marched his back further to press his hips back until Alec was as deep as he would get and touching him in all the right places.

"Oh my God, Alexander!" Magnus moaned, grinding his hips. "You feel so good, so big."

Alec pulled his hips back slowly, letting Magnus feel the stretch before snapping his hips forward, listening to Magnus' squeak of a whimper.

"And you are so fucking tight."

Alec punctuated each word with a thrust, building a rhythm that had the both of them moaning and groaning, Magnus shoving his hips back with every forward movement Alec made. Alec leaned over Magnus' back, listening to his little  _ ahs  _ and never faltering with his pace. He kissed Magnus' shoulder a few times, nipping at the skin and groaning at the salt taste. Then he let go of one of Magnus' hips to tangle his hand in his husbands hair, yanking gently until his head was craned back, forcing a loud moan from his mouth.

"Look at you, taking it so well." Alec mumbled against his ear. "I swear you were made for this, sweetheart."

Magnus cried out suddenly when Alec sawed over his prostate, sobbing out his words. "Oh f-fuck. Alec I'm so close."

Alec hummed, feeling his stomach tighten and his balls begin to draw up, knowing that he wouldn't be able to hold on much longer either. He pushed Magnus' face back down onto the pillow, not moving his hand as he picked up his pase fucking Magnus as hard as he could and listening to the sound of his thighs hitting Magnus' ass.

It didn't take long for either of them to come, Magnus holding on until Alec practically demanded he come untouched and only on his dick and Alec came just by listening to the sound of his husband fall apart.

Later, when they'd taken a shower and had round two in there aswell, they were curled up in bed Magnus' bead resting on his chest and his hand only covered in now two rings. Alec pressed a kiss to Magnus' forehead, listening as he drifted off peacefully.

In that moment he knew that spending forever with Magnus would be more than worth all the challenges they would face.

He'd spent the rest of his life convincing Magnus he was worth immortality if he had to.

He was worth everything.

**Author's Note:**

> Oof
> 
> I hope yall are enjoying, see you tomorrow!
> 
> Dont forget to check out the #cherrys25daysofmalec tag on Twitter for updates on this challenge!
> 
> Also all kudos and comments are very much appreciated :D
> 
> Love yall!


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